Generally, there are various kinds of thermal oxidizers to oxidize harmful gases, such as volatile organic compounds, resulting from process gases in industrial site and to discharge the oxidized products to the outside. Regenerative thermal oxidizers, which are capable of preheating inlet process gases using the high heat energy of outlet process gases resulting from combustion of the process gases, have advantages of saving energy and of efficiently eliminating harmful gases.
Conventional regenerative thermal oxidizers each include a combustion chamber which burns and oxidizes process gases, a heat exchanging part and a rotor which periodically rotates to supply or discharge the process gases into or from the combustion chamber. Process gases supplied from the rotor are burned in the combustion chamber after passing through the heat exchanging part. Thereafter, the burned process gases are discharged to the outside through the heat exchanging part and the rotor. In this process, a section of the heat exchanging part functioning to discharge gas stores heat energy from combustion gases. The heat energy is used to preheat process gases supplied from the rotor.
FIG. 1 is a partially exploded perspective view of a conventional rotary type regenerative thermal oxidizer.
With reference to FIG. 1, a flow of process gases in the conventional regenerative thermal oxidizer is as follows. The process gases are drawn into a combustion chamber 60 after passing through an inlet pipe 30, an inlet opening 22 of a rotor 20, a plurality of openings 12 of a distribution plate 10, and a heat exchanging part 50, sequentially. The process gases are burned in the combustion chamber 60 and are discharged to the outside after passing through the openings 12 of the distribution plate 10, an outlet opening 24 of the rotor 20 and an outlet duct 40.
An upper surface of the rotor 20 is in close contact with the distribution plate 10 having the plurality of openings 12. Some of the openings 12 formed on the distribution plate 10 correspond to the inlet opening 22 of the rotor 20 and the remainder of the openings 12 correspond to the outlet opening 24 of the rotor 20, thus providing inlet and outlet process gas flow paths, respectively. In other words, the openings 12 of the rotor 20 guide process gases passing through the inlet opening 22 to the heat exchanging part 50 and guide the process gases, which are burned after passing through the heat exchanging part 50, to the outlet opening 24 of the rotor 20. A partitioning unit (not shown) is provided between the heat exchanging part 50 and the distribution plate 10 to prevent the inlet process gases and the burned process gases from mixing with each other.
In the conventional regenerative thermal oxidizer, because the rotor 20 separates inlet and outlet process gases from each other, a flow capacity of process gases is determined by areas of the inlet and outlet openings 22 and 24 of the rotor. Accordingly, to increase the flow of process gases, that is, the ability to process the process gases, the sectional area of the rotor must be increased. This purpose can be achieved by increasing the rotor size. However, to operate a large rotor, a drive unit having high power consumption is required. Due to this feature, manufacturing costs of the regenerative thermal oxidizer and costs of operating it are excessively increased.
The increase in the size of the rotor causes difficulty in maintenance of an airtight state between the rotor and adjacent components. For example, the rotor 20 shown in FIG. 1 must be airtightly coupled to adjacent components, such as an inlet chamber 31, the outlet duct 40 and the distribution plate 10. To achieve the above-mentioned purpose, a sealing material is applied to predetermined portions of the rotor 20. The increase in the size of the rotor brings an increase in the area to which the sealing material must be applied. As a result, difficulty in providing a soundly airtight structure exists.
In the meantime, the regenerative thermal oxidizer must prevent inlet and outlet process gases from mixing with each other in the rotor. As well, the inlet process gas flow path and the outlet process gas flow path must be independently defined in a lower end of the rotor. Furthermore, in the regenerative thermal oxidizer shown in FIG. 1, the outlet duct 40 passing through the inlet chamber 31 is coupled to the rotor 20. As such, the conventional regenerative thermal oxidizer is disadvantageous in that the structure is very complex.